RSmetanyuk: dragonCurve with direction parameter

babel.config.js

@@ -0,0 +1,4 @@
+'use strict';
+ module.exports = {
+  presets: ['@babel/preset-env'],
+}; 

package.json

@@ -30,6 +30,10 @@
     "html-webpack-plugin": "^3.2.0",
     "husky": "^1.1.2",
     "jest": "^23.6.0",
+    "@babel/core": "*",
+    "@babel/preset-env": "*",
+    "babel-core": "7.0.0-bridge.0",
+    "babel-jest": "*",
     "node-sass": "^4.9.4",
     "sass-loader": "^7.1.0",
     "style-loader": "^0.23.1",

src/dragon-curve/index.js

@@ -1,3 +1,24 @@
-export const dragonCurve = n => {
-  // logic...
-};
+export const dragonCurve = (direction, n) => {
+  let result = '';
+  const directionIsArray = Array.isArray(direction);
+
+  const dragonCurveNext = (direction, dragonCurvePrevious = '') => {
+    const dragonCurvePreviousLength = dragonCurvePrevious.length;
+    let currentDirection = (direction === '') ? Math.round(Math.random()) : direction;
+    let result = '';
+
+    for (let i = 0; i < dragonCurvePreviousLength; i++) {
+      result = `${result}${currentDirection}${dragonCurvePrevious.charAt(i)}`;
+      currentDirection = Number(!currentDirection);
+    }
+    result = `${result}${currentDirection}`;
+
+    return result;
+  };
+
+  for (let i = 0; i < n; i++) {
+    result = dragonCurveNext(directionIsArray ? direction[i] : direction, result);
+  }
+
+  return result;  
+};

src/dragon-curve/index.spec.js

@@ -1,5 +1,31 @@
-import {dragonCurve} from './index'
+import {dragonCurve} from './index';
 
 describe('dragonCurve::', () => {
-  // need to implement
-});
+  it('Should return left direction Dragon Curve n-th order, as in original task', () => {
+    expect(dragonCurve(1, 1)).toEqual('1');
+    expect(dragonCurve(1, 2)).toEqual('110');
+    expect(dragonCurve(1, 3)).toEqual('1101100');
+    expect(dragonCurve(1, 4)).toEqual('110110011100100');
+  });
+
+  it('Should return right direction Dragon Curve n-th order', () => {
+    expect(dragonCurve(0, 1)).toEqual('0');
+    expect(dragonCurve(0, 2)).toEqual('001');
+    expect(dragonCurve(0, 3)).toEqual('0010011');
+    expect(dragonCurve(0, 4)).toEqual('001001100011011');
+  });
+
+  it('Should return random direction Dragon Curve n-th order', () => {
+    const result = dragonCurve('', 4);
+    expect(/^[0-1]{15}$/.test(result)).toEqual(true);
+    expect(parseInt(result.slice(0, result.length / 2), 10) + 
+      parseInt(result.slice(result.length / 2 + 1).split('').reverse().join(''), 10)).
+      toEqual(1111111);
+  });
+
+  it('dragonCurve should receive direction parameters as an array', () => {
+    expect(dragonCurve([1,1,1,1], 4)).toEqual('110110011100100');
+    expect(dragonCurve([0,0,0,0], 4)).toEqual('001001100011011');
+    expect(dragonCurve([1,0,0,0], 4)).toEqual('001001110011011');
+  });
+});

src/rotate-matrix/index.js

@@ -1,4 +1,21 @@
 export const rotateMatrix = arr => {
-  // logic...
+  const rusalt = [];
+  const arrLength = arr.length;
+  //const arrflat = arr.flat(); так коротше але тести чомусь не проходять. На jsfiddle працює.
+  const arrflat = arr.reduce((acc, val) => acc.concat(val), []);
+  const arrflatObj = arrflat.map((el,i) => {
+    return {
+      element: el, 
+      weight: i % arrLength
+    };
+  });
+  const arrflatObjSorted = arrflatObj.sort((a, b) => {
+    return a.weight - b.weight;
+  });
+  const resultArrFlat = arrflatObjSorted.map(a => a.element);
+  while (resultArrFlat.length > 0) {
+    rusalt.push(resultArrFlat.splice(0, arrLength));
+  }
+  return  rusalt;
 };
 

src/rotate-matrix/index.spec.js

@@ -1,5 +1,22 @@
-import {rotateMatrix} from './index'
+import {rotateMatrix} from './index';
 
 describe('rotateMatrix::', () => {
-  // need to implement
+  it('Should return rotated matrix', () => {
+    expect(rotateMatrix([
+      [1, 2],
+      [3, 4]
+    ])).toEqual([
+      [1, 3],
+      [2, 4]
+    ]);
+    expect(rotateMatrix([
+      [1, 2, 3],
+      [4, 5, 6],
+      [7, 8, 9]
+    ])).toEqual([
+      [1, 4, 7],
+      [2, 5, 8],
+      [3, 6, 9]
+    ]);
+  });
 });